The Taliban on Saturday declared the start of a spring offensive in Afghanistan, warning that insurgents plan to attack foreign troops, Afghan security forces and government officials in coming days.

In a statement, the Taliban warned civilians to avoid public gatherings, military bases and convoys, as well as government buildings.

“All Afghan people should bear in mind to keep away from gatherings, convoys and centers of the enemy so that they will not become harmed during attacks of mujahedin against the enemy,” the statement said.

The statement said that in addition to troops, the targets of their operation would be high-ranking officials within President Hamid Karzai’s government, members of the Cabinet and lawmakers, as well as businessmen working with NATO forces.

United Nations officials, who lost eight staff members in an attack last month in the northern city of Mazar-i-Sharif, appealed to the Taliban not to target noncombatants.

“Parties to the conflict must not deliberately attack, target or kill civilians,” said Staffan de Mistura, who heads the U.N. mission in Afghanistan. “I call on the Taliban to carry out their previously stated decision to avoid civilian casualties. Afghan civilians have paid the price of war for too long. It is more urgent than ever that all parties act to prevent this suffering.”

North Atlantic Treaty Organization commanders have trumpeted successes in Afghanistan since 30,000 additional U.S. troops arrived last year, although they also predicted a spike in violence with the arrival of the spring and summer fighting season. On Friday, senior military officials and Western diplomats warned of a surge in militant attacks during the coming week.

Violence across Afghanistan hit record levels in 2010, with civilian and military casualties the worst since U.S.-backed Afghan forces dislodged the Taliban regime in 2001.

The Pentagon said in a biannual report Friday that the increase in violence was attributable in part to increased offensives against insurgent havens and mild winter weather that kept insurgents active.